As I mentioned deeper in the response tree, you might need to calculate the page, especially if you have DisplayAlerts = 0 or the cell references data from another sheet.
in reply to Reading from Excel
It's happened to me before.
use Win32::OLE qw(in with);
use Win32::OLE::Const 'Microsoft Excel';
my $Excel = Win32::OLE->GetActiveObject('Excel.Application')
|| Win32::OLE->new('Excel.Application', 'Quit');
my $Book = $Excel->Workbooks->Open($excelfile);
my $Sheet = $Book->Worksheets("Sheet1");
#The rest of your GET code here
Flex the Geek